Summing Amplifier

Prelab and data table of measured voltages

constructed circuit

While the lab asked us to make a closed loop gain of around 2, we adjusted ours to be much smaller at 0.1912. We ran into problems with having the op amp getting saturated when using Vb outside of -2 to 2V. Most of the measured data points had a percent difference of less then 10 %. There were two points, Vb at -3V and 5V that gave differences of 12.6% and 10.6%. This makes sense that the greatest percent difference was for data points that had the biggest voltages used since they would be closer to saturation for the op amp.

Inverting Voltage Amplifier

Circuit diagram and
Vin/Vout table

Graph of Vin vs Vout

Constructed circuit

Based on the values we used for R1 and R2, our calculated gain was -0.470. We had to use a smaller ratio as we were having problems with our op amp reaching saturation with a higher closed loop gain. As can be seen in our graph, the slope of the line is close to the calculated gain with a percent difference of 5.68%. This was caused by the one outlier point we have in our data. 

Thevenin's Theorem

The Rth we calculated was 7.6k ohms. Our calculated Voc was nearly identical with what we measured in Analog Discovery.

Circuit for part 2(measuring voltage
between nodes A and B)

  

RL added to circuit
(RL was 7.5k ohms)

Actual measurement of open circuit voltage

Measured Voltage across RL

Dusk-to-Dawn Light

Prelab

Voltage of photocell in light(yellow)

Voltage of photocell in darkness(yellow)

Mesh Analysis 1, 2, & 3

Mesh Analysis 1

Since the same circuits were utilized from the previous nodal labs, we used the same readings and just worked out the prelab for each one.  For Mesh 1, there was a 1.13% difference for V1, and 1.31% for V2. This is minimal and even closed then what was achieved with the nodal lab.

Mesh Analysis 2

The voltage for V1 should of been 5 Volts as that resistor was in parallel with the 5V source.  We worked out 4.998V in our analysis.

Mesh Analysis 3

For this lab, we achieved a percent difference of 0.73% for V1. Using ohm's law, the calculated i1 using the measured V1 is -0.274 micro amps.  This gives a percent diff of 3.72%.